Optimization of Multimedia Flows over Data Networks : the Core Location Problem and the Peakedness Characterization

Acknowledgements First of all, I wish to thank my supervisors, Benoit Macq and Laurence Wolsey, for their guidance and continuous support during these four years. I am very grateful not only for their technical expertise but also for their ability to make me self-confident in moments of doubt. Moreover , working on a subject at the frontier of their respective research areas has been a very rewarding experience. The results presented in Chapter 3 were obtained in collaboration with Michel Goemans during my stay at the Massachusetts Institute of Technology. I wish to express him my deep gratitude for having offered me the opportunity to spend a wonderful year in Boston. I also owe many of the ideas presented in this thesis to fruitful discussions with colleagues at CORE and at the TELE lab. I am in particular very grateful to Philippe Chevalier who partly supervised the work described in the second part of this thesis. Many thanks also to the members of the examination committee for their numerous and helpful comments which allowed me to improve the manuscript. When doing full-time research, friendship is certainly an indispensable ingredient to preserve one's mental health. Besides the old good friends, many colleagues have intensely contributed to create a very friendly and relaxed working atmosphere. Last but not least, I thank my parents and family for their everlasting love and support. I can hardly say how thankful I am to Isa for her tremendous support and patience throughout these four years and more particularly during the last few months. This thesis is dedicated to them.